We propose to evaluate the conversion of the radiology department from a slow speed screen-film combination (par) to a high speed rare earth system (4 times par). We shall investigate these screens in all areas of clinical work that the department does (i.e., chest films, bone films, barium studies, IVPs, etc.). The basic objectives of this study include a clinical evaluation of both the par speed and the rare earth screens and a corresponding comparison of diagnostic accuracy and confidence level. In general radiography we will determine whether high resolution and low noise characteristics are necessary to obtain films which the radiologist can confidently interpret. Based on previous studies we feel that with appropriate changes in radiographic technique (kVp, exposure time, focal spot size, etc.) overall image quality need not be sacrificed with a 4X par system. This shall be studied by having a group of radiologists using specially designed rating forms evaluate patient films from all clinical areas. We shall also determine from this study the patient exposure for all routine exams and the radiographic technique modifications, which are permitted by the adoption of the high speed rare earth screens. We shall also study any problems encountered with our present equipment as we implement these screens. Finally, we shall study the effect of carbon fiber cassette fronts on image quality and patient exposure for both general radiographic and special procedure exams.